Remarkably, granule cells (GCs) of the olfactory bulb are continuously born throughout life, providing an excellent neuronal model for the study of both developmental and adult neurogenesis of inhibitory neurons in the brain. As with GCs born during development, cells born in the adult olfactory bulb must establish functional connections with existing neuronal components, including the fibers of the noradrenergic system. This system plays an essential role in sensory information processing in the bulb. The aims outlined in this application seek to understand the physiological role and cellular mechanisms by which the noradrenergic system modulates GC function in the olfactory bulb. In the first two aims, we propose to investigate the cellular mechanisms and physiological role of the excitatory action of noradrenaline on GCs in the main and accessory olfactory bulb. In the last aim, we propose to determine the role of the noradrenergic system on adult neurogenesis of GCs in the context of olfactory mediated behaviors.